RED-3800: Redo HasScrollbar directive

src/lib/directives/has-scrollbar.directive.ts

@@ -1,27 +1,33 @@
-import { ChangeDetectorRef, Directive, ElementRef, HostBinding, HostListener, OnChanges, OnInit } from '@angular/core';
+import { ChangeDetectorRef, Directive, ElementRef, HostBinding, OnDestroy, OnInit } from '@angular/core';
 
 @Directive({
     selector: '[iqserHasScrollbar]',
     standalone: true,
 })
-export class HasScrollbarDirective implements OnInit, OnChanges {
+export class HasScrollbarDirective implements OnInit, OnDestroy {
     @HostBinding('class') class = '';
-
-    constructor(
-        protected readonly _elementRef: ElementRef,
-        protected readonly _changeDetector: ChangeDetectorRef,
-    ) {}
+    private readonly _resizeObserver: ResizeObserver;
 
     get hasScrollbar() {
         const element = this._elementRef?.nativeElement as HTMLElement;
         return element.clientHeight < element.scrollHeight;
     }
 
+    constructor(
+        protected readonly _elementRef: ElementRef,
+        protected readonly _changeDetector: ChangeDetectorRef,
+    ) {
+        this._resizeObserver = new ResizeObserver(entry => {
+            this.process();
+        });
+
+        this._resizeObserver.observe(this._elementRef.nativeElement);
+    }
+
     ngOnInit() {
         setTimeout(() => this.process(), 0);
     }
 
-    @HostListener('window:resize')
     process() {
         const newClass = this.hasScrollbar ? 'has-scrollbar' : '';
         if (this.class !== newClass) {
@@ -30,7 +36,7 @@ export class HasScrollbarDirective implements OnInit, OnChanges {
         }
     }
 
-    ngOnChanges() {
-        this.process();
+    ngOnDestroy() {
+        this._resizeObserver.unobserve(this._elementRef.nativeElement);
     }
 }